Draw type wrapping machine



Sept. 25, 1962 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE Filed Nov. 4. 1957 9 Sheets-Sheet 1 II M l l -34 I l %ll ggg\g\ /am /70 '72 g; w wmm 4 ZeZZ, By 5%), AQMM 9 %JM} ATTORNEYS.

INVENTORS Sept. 25, 1962 Filed NOV. 4. 1957 J. F. MARKLEY ETAL DRAW TYPE WRAPPING MACHINE 9 Sheets-Sheet 3 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE I Sept. 25, 1962 9 Sheets-Sheet 4 Filed Nov. 4. 1957 /N 1 5 N TORS By 972W W Z4 ATTORNEYS.

P 1962 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE 9 Sheets-Sheet 5 Filed Nov. 4. 1957 /N VE N TORS BY fieamw 5 ATTORNEYS.

Sept. 25, 1962 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE 6 m 1 i M m zwfi m W W m if M Filed NOV. 4. 1957 Sept. 25, 1962 J. F; MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE Filed Nov. 4. 1957 9 Sheets-Sheet 7 lNVENTORS:

ATTORNEYS.

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Sept. 25, 1962 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE Filed Nov. 4. 1957 9 Sheets-Sheet 8 ATTORNEYS.

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o o .298 3/0 I p 1952 J. F. MARKLEY ETAL 3,055,154

DRAW TYPE WRAPPING MACHINE 9 Sheets-Sheet 9 Filed NOV. 4. 1957 M IMENT VERT c CLOSING fi CLO'SED jg LOCKED ALLOWABLE FEED PERIOD LEFT \SETTING TIME CAMSHAFT DEGREES 00 RIGHT ATTORNEYS.

Patented Sept. 25, 1962 3,055,154 DRAW TYPE WRAPPING MAC John F. Markley, Saddle Brook, and .Iohn S. Eartlo, Oakland, N.J., and Richard B. Brigham and Lyman L.

Campbell, Anderson, Ind, assignors to Lynch Corporation Filed Nov. 4, 1957, Ser. No. 694,399 7 Claims. (Cl. 53-182) This invention relates generally to an automatic packaging machine, and more particularly to an improved machine of the type adapted to form a continuous hollow tube from a fiat web of packaging material and to thereafter draw, fill, seal, and cut individual pillow-type packages.

Pillow-type packaging has become an increasingly popular and advantageous technique for providing individual sealed packages of bulk materials, including granular, powdered, and liquid substances, and of individual and multiple articles. The advent of strong, pliant and transparent packaging materials, such as thermoplastic and other synthetic films, has further increased the interest in pillow-type packaging. Although numerous machines have been previously known for effecting pillow-type packaging, both by single-action and dual-action draw bar methods, and both by single-tube and multiple-tube structural arrangements, there has been an increasing need for improved efliciency, speed, reliability of performance, flexibility of adjustment, and simplicity of maintenance for such types of packaging machines.

It is, therefore, a primary object of this invention to provide an improved pillow-type packaging machine having tube-forming, sealing, and drawing means for automatically forming, filling, sealing, and separating packages for measured amounts of various materials in individual pillow-type bags.

It is another object of this invention to provide a novel mechanical drive for a draw bar type of pillow-type packaging machine, wherein package length may be readily adjusted during machine operation and without change or substitution of parts.

It is another object of this invention to provide a novel mechanical and hydraulic actuation means for effecting sealing closure of the draw bar of a pillow-type packaging machine, wherein an accurate hydraulic sealing pressure of predetermined and constant magnitude is provided and maintained throughout the drawing stroke.

It is another object of this invention to provide automatic bag length registration means of a novel lock release type for insuring the maintenance of the correct alignment and length of printed bag materials in a pillow-type packaging machine.

It is another object of this invention to provide a sealing die structure for a pillow-type packaging machine having package cut-off means mounted therein for automatic actuation intermediate the length of the package drawing stroke.

It is another object of this invention to provide novel sealing and drawing dies for a pillow-type packaging machine adapted to effect impulse sealing and cold wire cutting of polyethylene packaging material.

Further objects and advantages of this invention will become apparent as the following description proceeds, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawing, in which:

FIGURE 1 is a fragmentary perspective view, with parts broken away and omitted, illustrating the novel drive mechanism for a dual-action draw bar machine constructed in accordance with the principles and features of the present invention.

FIGURE 2 is an elevational view illustrating the progressive manner of package formation in a pillow-type packaging machine to which the present invention is directed.

FIGURE 3 is a vertical sectional view taken through the entire supporting frame of a machine constructed in accordance with the present invention and embodying the drive mechanism of FIGURE 1.

FIGURE 4 is another vertical sectional view taken substantially as indicated along the line 4--4 on FIG- URE 3.

FIGURE 5 is a horizontal sectional view taken through the sealing die carriage assemblies.

FIGURE 6 is a fragmentary vertical sectional view taken through one of the sealing die carriage assemblies, substantially as indicated by the line 6-6 on FIGURE 5.

FIGURE 7 is another fragmentary vertical sectional view taken substantially as indicated along the line 7-7 on FIGURE 6.

FIGURE 8 is a horizontal sectional view taken substantially as indicated along the line 88 on FIGURE 7.

FIGURE 9 is a vertical sectional View taken substantially as indicated along the line 99 on FIGURE 8.

FIGURE 10 is a top plan view of a pair of sealing dies particularly adapted for use with polyethylene packaging materials.

FIGURE 11 is an end view taken substantially as indicated along the line 1111 on FIGURE 10.

FIGURE 12 is a vertical cross-sectional view taken substantially as indicated along the line 1212 on FIG- URE 10.

FIGURE 13 is a partial horizontal sectional view taken through the machine and looking downwardly on a supply roll assembly for the packaging material.

FIGURE 14 is a vertical sectional view taken substantially as indicated along the line l414 on FIGURE 13.

FIGURE 15 is a timing chart indicating the over-all cyclical operating sequence of the entire machine and its various component assemblies and controls.

FIGURE 16 is a diagrammatic view of the hydraulic pressure circuit for supplying the carriage hydraulic rods.

FIGURE 17 is another diagrammatic view of the related hydraulic pressure circuit between the carriage hydraulic rods and the die clamping cylinders, and

FIGURE 18 is an electrical circuit diagram showing a thermostatic control for the die heaters of the sealing die assembly embodiment of FIGURES 9 and 10.

Referring more particularly to FIGURES 3 and 4 of the drawing, we have indicated generally at 10 a single tube draw-type wrapping machine constructed in accordance with, and embodying the features of, the present invention. A frame generally designated at 12. provides both a supporting and enclosing structure for the operating components of the machine. The machine structure may be divided into three zones or sections for purposes of description. As seen in FIGURE 3, the machine comprises an upper or tube-forming section A, a center or package-forming and drawing section B, and a lower or drive section C. An upper plate 14, center plate 15 and lower plate 16 of the frame 12 serve as support and guide means for the various structural components of the machine sections.

Referring now more particularly to FIGURE 4, the major components of the drive section C will be first described so that the actuation and operative response of the structure comprising the package-forming and drawing and tube-forming sections will be more readily understood as the descriptions of those sections are taken up in turn.

An electric motor M of suitable size and power, such as a /3 horsepower motor, is mounted below the center plate 15 in suspended relation therefrom. The motor M 3 1. provides a drive shaft which is coupled by means of a bearing, pulley and belt assembly 18 to the input shaft of a gear reducer 20. V-belt pulleys are used in the assembly'18 so as to permit manual adjustment of the effective pulley diameters for varying the drive speed as desired during machine operation.

The output drive shaft of the gear reducer 20 is coupled by means of a link chain and sprocket assembly 22 and idler sprocket 24 to a generally horizontally disposed main power and cam shaft 26, supported by the frame 12 upon suitable rotary bearing mounts.

The sealing jaw carriage assemblies, which are hereinafter described in detail, are carried for reciprocatory movement by left-side and right-side pairs of vertically reciprocable carriage rods. The left-side rods are indicated at 28 and 3t and the right-side rods are indicated at 32 and 34, as best seen in FIGURE 1 of the drawing. Both pairs of carriage rods extend slidably through the upper and center plates 14 and 15. Corresponding upper and lower pairs of roller bearing assemblies, 36 and 38 respectively, are provided for gliding support of the carriage rods. The left-side carriage rods 28 and are fixedly secured at their lower ends to a carriage raising bracket 40. The right-side rods 32 and 34 are similarly secured to a corresponding carriage raising bracket 42 (see FIGURE 1). The carriage raising brackets 40 and 42 are pivotally secured by means of yoke and rod assemblies, 44 and 46 respectively, to the opposite yoked pivot ends of a walking beam 48 (see also FIGURE 3). The walking beam 48 is centrally supported for pivotal rotation upon a shaft and bearing assembly 50 carried by the frame lower plate 16. It will be apparent that rotary oscillation of the walking beam 48 about its center pivot shaft 50 will serve to efiect alternate-phase reciprocation of the respective left-side and right-side pairs of carriage rods. That is, as the left-side carriage rods 28 and 30 are elevated, the right-side carriage rods 32 and 34 are lowered, and vice versa.

Actuation of the walking beam '48 for oscillating movement is effected by a vertical movement cam 52 carried by the main shaft 26 and rotatably driven thereby (see FIGURES l and 4). The cam 52 is of the two-way positive action type and cooperates with the roller of a cam yoke 54 so as to effect vertical reciprocation of the cam yoke in a slidable manner about the rotatably driven main shaft 26. A rod 56 is carried by the cam yoke 54 and is vertically slidable through the frame center plate 15. A suitable guide and bearing bushing 58 is provided on the plate 15 for slidably supporting the rod 56 during its reciprocatory movement. A lever 60 is pivotally connected at its one end to the cam yoke rod 56 intermediate the ends of the latter. The lever 60 is provided with an elongated transverse slot 62, and is slidably mounted for reciprocating movement Within a bearing plate portion 64, fixed to the lever 69. A slide block 66 is rotatably carried by a stroke adjustment slide member 68 and is also slidably carried within the bearing plate portion 64. A connector pin 70 extending through the lever slot 62 serves to support the block 66 in its slidably mounted relation. The stroke adjustment slide member 68 .is carried by a gib means 72 below the frame center plate 15, and maybe adjustably secured at various predetermined positions along the length of the gib means 72. A connectorrod 74 pivotally interconnects the opposite or free end of the lever 60 to the walking beam 48. An adjustment rod, not shown, may be secured to the slide member 68 and extended beyond the frame 12 for convenient external manual adjustments.

I It 'will be apparent that predetermined selective positioning of the slide means 68 along the length of the gib means 72 will serve to vary the position of the pivot pin 70 along the length of the stroke adjustment lever 60. Such selective positioning serves to vary the fulcrum point and effective lever length so as to vary the height of stroke of the connector rod 74 as desired. The stroke height of the adjustment connector rod 74, in turn, varies the amplitude of oscillation of the walking beam 48, and

thereby the height of the strokes of the carriage rods. As

will be hereinafter pointed out in connection with the 5 formation of the packages, this feature of rod stroke adjustment provides a simple and convenient means for quickly varying the desired package length without necessity for replacing parts or discontinuing machine operation.

As best seen in FIGURE 1 of the drawing, a pair of sealing jaw carriages, left-side and right-side respectively, are fixedly carried by the opposed pairs of left-side and right-side reciprocable carriage rods 28, 30 and '32, 34.

Each of the sealing jaw carriages and 82 comprises a 15 vertically spaced pair of generally horizontal carriage plates 84 and 86. A back plate 88 extends vertically between the upper and lower plates 84 and 86. Particular reference will now be made to FIGURES 5 and 6 of the drawing in describing the detailed structure of each of the sealing jaw carriage assemblies. A pair of die holders Q0 and 92, front and back respectively, serve to support the sealing dies which efiect package sealing and cutting, in a manner to be hereinafter described, and are mounted for relative movement between closely adjacent and widely spaced relative positions. In FIGURE 5 the left-side carriage 89 has been shown with its sealing jaws in widely spaced or open position, and the right-side carriage 82 has been shown with its sealing jaws in closely adjacent or closed position. It will be understood that both the left-side and right-side carriage structures are substantially identical, and only one of the carriages will the described in detail.

Inner and outer pairs of tubular carriage spacer members 94, and 96, 97 extend between the upper and 35 lower carriage plates 84 and 86. Inner and outer pairs of wrist pins 8, 99 and 1G0, 101 are supported within the carriage spacers for rotary movement about their longitudinal axes, as best seen in FIGURE 6. A pair of upper and lower die actuator arms. extend integrally 40 and horizontally from each of the carriage spacers 94 to 97, the inner and outer pairs of arms being indicated in FIGURE 5 at 102, 133 and 194, 105. The inner pair of wrist pins 98 and 106 extend downwardly and rotat ably through the lower carriage plate 86, and serve to 45 carry a pair of meshed actuator gears 106 and 108.

Vertically spaced pairs of inner and outer pivot bosses 110, 111 and 112, 113 are provided by the front and back die holders 9i) and 92, respectively (see FIGURE 5) for pivotally mounting the die holders for arcuate swinging 5O movement about vertical axes of rotation relative to the corresponding upper and lower die actuator arms 102 to 105. In this way, pivotal movement of the die actuator arms about the wrist pins will serve to effect a corresponding arcuate movement of the front and back die 55 holders 9%) and 92 toward and away from each other.

' Left-hand and right-hand die arm closing shafts 114 and 116, of square or otherwise non-round cross section, are fixedly mounted at their lower ends upon the corresponding left-side and right-side carriage raising brack- O ets 40 and 42 (see FIGURE 1). The upper ends of the closing shafts 114 and 116 are secured to the actuator gears 106 of the left-side and right-side carriage assemblies 8t and 82, respectively (see FIGURE 6). It will be apparent that rotation of the square closing shafts 1 14 and 116 will effect simultaneous rotation of the inner pairs of die actuator arms 102, 103.

The square closing shafts 114 and 116 extend downwardly through the frame center plate 15 and a guide bracket assembly 118 suspended therebelow (see FIG- 70 URE 3). Turn arms 120 are pivotally supported by the guide brackets 118 and carry opposed pairs of roll pins 122 for engagement with the four fiat sides of the corresponding square closing shafts. In this way, the shafts are free to vertically reciprocate relative to the horizon- 75 tally fixed turn arms 120, while being coupled ther so that rotation of the turn arms 120, in a horizontal plane will effect corresponding rotation of the square shafts about their longitudinal axes. Connector rods 124 are pivoted at their one end to the turn arms 120 for rotation about a vertical pivot axis, and are pivoted at their other end to a power lever 126 for rotation about a horizontal pivot axis (see FIGURE 1). The lower ends of the power levers 126 are pivotally mounted for rotation about a horizontal axis by suitable bearing brackets 128 carried upon the frame lower plate 16 (see FIGURE 4). Cam follower rollers 130 are provided by each of the power levers 126 intermediate their ends and are cooperatively received within the groove of a corresponding face-type power cam, the left-hand and right-hand cams being designated at 132 and 134 respectively (see FIGURE 1). The cams 132 and 134 are of the two-way type and effect positive oscillation of the power levers 126 as the main drive shaft 26 is rotatably driven.

It Will be apparent that the drive section of the machine serves, as the main power and cam shaft 26 is driven, to continuously rotate the vertical movement cam 52 and the left-side and right-side sealing jaw closing cams 132 and 134. The vertical movement cam 52 transmits a reciprocatory movement to the walking beam 48, and the oscillation of the walking beam, which may be variably adjusted in its amplitude, serves to alternately reciprocate the left-hand and right-hand pairs of carriage rods 28, 38, and 32, 34, thereby eifecting reciprocation of the sealing jaw carriages 8i) and 82. Continuous rotary drive of the jaw closing cams 132 and 134 is transmitted through the members 126, 124 and 120 to effect rotation of the corresponding die arm closing shafts 114 and 116 in alternate opposed directions, thereby rotating the pairs of die actuator arms for alternately closing and opening the opposed die holders 96 and 92 of the left-side and right-side sealing jaw carriages 80 and 82. The timed cycle of operations, as determined by the shapes of the cams, is such that closure of the jaws of one carriage assembly corresponds with opening of the jaws of the other carriage assembly, and the jaws of each assembly are closed during downward reciprocatory movement for effecting package drawing, while being open during upward reciprocatory movement to permit the jaws of the opposed carriage and its package to be drawn downwardly therebetween without risk of obstruction.

The closing movement of the sealing jaws, as described thus far, is effected entirely by mechanical means, and serves to bring the faces of the opposed sealing dies into kissing contact, but does not serve to exert a positive sealing pressure force. The actual locking force for effecting a positive sealing squeeze and tight gripping of the packaging material between the die faces is efiected by a separate hydraulic-mechanical circuit, which will now be described in detail. This method and structure of closing the sealing dies in two distinct stages, the first being an entirely mechanical action for bringing the dies into lightly contacting proximity, and the second being a combined hydraulic and mechanical action for insuring a constant and predetermined sealing pressure of the dies in locked cooperation, constitutes a highly important feature of this invention. 2

The structure for effecting the locking engagement of the sealing dies will now be described in detail. The front and back die holders 90 and 92 provide inner and outer boss portions 140, 141 and 142, 143, respectively, adjacent their base portions and their pivotal connections with the die actuator arms (see FIGURE A hardened steel slide rod extends through the die holder bosses, the rod of assembly 80 being indicated at 144 and the rod of assembly 82 being indicated at 146. Referring more particularly to assembly 80 of FIGURE 5, a compression spring 147 is disposed intermediate the bosses 140, 141 and a similar spring 148 is disposed intermediate the bosses 142, .143. The end of the slide rod 144 6 at die holder '98 is fixedly secured to the bosses 141 by means of a jig assembly 156. The opposite end of the slide rod 144, adjacent the die holder 92, is freely slidable through the bosses 142 and 143. A clamp block 152 is slidably carried by the rod 144 and held in biased engagement against the boss 142 by the spring 148.

A hydraulic cylinder 154 is provided adjacent the boss 142, and has an inlet 156 communicating with a source of hydraulic fluid. A piston 158 is slidable within the cylinder 154, and carries an actuator pin 160 which is adapted to engage and exert a force against a laterally extending portion of the clamp block 152.

The parts as seen in assembly of FIGURE 5 represent the inactive state of the hydraulic locking mechanism. The identical corresponding parts of assembly 82 have been shown in their relative positions upon actuation of the hydraulic locking mechanism after the die holders have been mechanically moved into initial closing contact. Hydraulic pressure has been introduced through the inlet 156 to the interior of the hydraulic cylinder 154, thereby causing an outward movement of the piston 158 and its actuator pin against the clamp block 152. The force thus exerted serves to effect a pivoting of the clamp block 152 relative to the adjacent die holder boss The edges of the clamping block bore, through which the slide rod extends, efiiect a biting engagement and gripping of the slide rod as the clamping block 152 tends to pivot. In this way, a slight shifting of the back die holder 92 toward the front die holder 90 is effected. As long as the hydraulic pressure is maintained Within the cylinder 154, this compressive movement of the die holders toward each other beyond their initial mechanical positioning by the die actuator arms will be maintained, thereby effecting a positive locking action.

In order to introduce hydraulic fluid pressure within the hydraulic cylinders of the respective carriage cylinders 80 and 82, and maintain such pressure during the full time of downward drawing movement of a corresponding carriage assembly in alternate sequence with the other carriage assembly, a pair of sequentially operated hydraulic pumps 162 and 164 are provided within the drive section of the machine (see FIGURE 1). A pair of lock cams 166 and 168, corresponding respectively to locking actuation of the carriage assemblies 80 and 82, are carried by the main cam shaft 26. Although the cams 166 and 168 are of identical shape, they are disposed 180 out of phase so as to effect alternate cyclical actuation of the pumps 162 and 164. A lever 170 is pivotally mounted upon hearing means 172 adjacent each of the lock cams 166 and 168. Each lever 170 provides a cam roller 174 at its one end for cooperative engagement with the corresponding lock cam. The other end of each lever 170 is pivotally secured to an actuator rod 176 of the respective pumps 162 and 164.

In order to deliver hydraulic fluid to the cylinders 154 of each of the carriage assemblies 80 and 82, while avoiding any exposed hydraulic lines in the packaging forming and drawing section of the machine, the carriage rods 30 and 34 each provide hydraulic bores 180 and 182, respectively, for the passage of fluid upwardly there through. The upper ends of the bores 180 and 182 communicate with the corresponding inlets 156 of the hydraulic actuator cylinders 154. The lower ends of the bores 180 and 182 communicate with flexible conduit means 184 and 186, respectively, secured to the corresponding carriage raising brackets and communicating with the corresponding hydraulic pumps. Preferably, the hydraulic bores extend throughout the length of the carriage rods, and a bleeder plug 188 (see FIGURE 3), may be provided at the uppermost end of the carriage rods for bleeding purposes.

When the walking beam 48 has elevated a pair of carraige rods and the sealing body assembly carried thereby to an uppermost position within the package forming and drawing section B of the machine, the front and back die holders will be in their full open positions. The'clo'sing baths 132 and 134 are then operative to effect a mechani cal closing movement of the die holders through the' pivoting action of the actuator arms. This action serves to position the faces of the opposed sealing dies carried by the die holders in contacting engagement. The lock cams 166 and 168 are operative to energize delivery of a hydraulic pressure to their corresponding hydraulic locking cylinder, thereby pivoting the clamp block and effecting a positive squeeze and tight gripping of the packaging material between the die faces. This gripping engagement is maintained in locked relation during the downward movement of the now closed carriage assembly in response to the action of the walking beam 48. The closing action of the dies, therefore, is effected in two different and separately actuated and controlled stages.

' The sealing die assemblies carried by the front and back die holders 90 and 92 of the left-hand and righthand scaling jaw carriages 80 and 82 are replaceably mounted for selective interchangeability to suit the requirements of the particular packaging material being used. The sealing die assemblies perform three functions in the package forming process. First, the opposed die faces of each carriage exert a sealing pressure and apply a fusing heat for effecting a complete end closure of the hollow tube of packaging material. Second, the dies are maintained in tight contacting engagement for effecting a secure gripping of the packaging material to permit it to be drawn downwardly as the carriage is lowered. Third, after sealing and during the downward drawing movement, a cutting of the sealed package end. is effected to sever the upper sealed edge of a fully formed lower package from the lower sealed edge of a partially formed upper package thereabove.

In FIGURES 8 and 9 of the drawing, we have illustrated the carriage 82 provided with a sealing die assembly structure for use with conventional packaging materials such as cellophane and heat-sensitive coated papers. The opposed die holders 90 and 92 fixedly carry a hot die body 200 and a cold die body 202, respectively. The hot die body 200 is disposed forwardly of and spaced from the die holder 90 by means of a die spacer body 204. Each of the die bodies provide opposed hot die faces 206 of serrated surface form for meshing engagement of the tube of packaging material thcrebetween. The cold die body 202 comprises a pair of horizontally superposed portions separated by means of a die spacer so as to define a slide cavity 228 therebetween. Suitable bolts 209 and 210 maintain the cold die body portions in fixedly mounted relation within the die holder 92.

The die spacer body 264 of the hot die assembly is floatingly mounted within its die holder 90 by means of a central pivot pin 212 and a pair of spring biasing assemblies 213 at opposite sides thereof. In this way, a slight yawing movement of the hot die body face in a horizontal plane is permitted relative to the cold die body face for insuring full surface alignment thereacross when the die bodies are in engaged relation. A die heater element 214 of generally U-shape and of the 'Calrod type or the like is mounted within a suitable recess in the spacer 204 at its interface with the body 200, and serves when energized to effect heating of the die body .face.

A knife blade 216 is slidably mounted within the slide space 208 of the cold die body 222. A knife shifter .bar assembly 218 is mounted within the die body 292 and provides bearing pins and roller 220 for cooperation with diagonal slots 222 formed within the knife blade 216. A bar spring 223 provides a biased mounting for ,the slidable bar 218 normally tending to withdraw the knife blade 220 into the recess 208 within the body 202. A'slidable linkage assembly 224 abuts the inner end of the -bar 218 and extends through a slide boss 226 fixedly provided with any heat energization.

carried by the sealing jaw carriage assembly 82, and provides an actuator roller 230 at its free end. A biasing spring 228 serves to bias the roller 230 in a direction toward an actuator cam 232 which is suitably mounted upon the machine frame 12 at a selected point substantially midway along the average height path of the machine drawing operation, for cooperative engagement with the roller 230 as it passes by.

e In this way, downward movement of the sealing jaw carriages with their sealing die assemblies in engaged relation results in a cooperative engagement of the knife actuator roller 230 with the cam 232, thereby sliding the linkage assembly 224 toward the sealing die assemblies, or toward the left as seen in FIGURE 8 of the drawing. This sliding movement of the knife shifter bar 218 causes the rollers 220 to move along the slots 222 and shift the knife blade 216 outwardly from the cold die body 292, across the sealed packaging material, and into a suitable receptor cavity 208' within the hot die body 200.

This novel and improved assembly of parts for a sealing die assembly, to be used in a machine of the type for which the present invention is intended, achieves an extremely compact and efficient knife cutting arrangement, wherein the cutting operation is not performed until substantial heat sealing has been effected and a substantial portion of the downward drawing movement of the sealing jaw carriage has been completed. The action is entirely mechanical.

Certain thermoplastic packaging materials, and particularly polyethylene, have unique physical characteristics which prevent efficient knife cutting in the manner of the sealing die assemblies previously described for use with cellophane and the like. We have provided a sealing die construction particularly adapted and suited for use with polyethylene in a pillow-type packaging machine. Referring now more particularly to FIGURES 10 to 12 of the drawing, we have illustrated a pair of polyethylene sealing dies adapted to be carried by the die holders and 92 of the machine structure heretofore described. A hot die body 24!) and a cutting die body 242 are provided. The cutting die body 242 is a cold assembly fixedly secured within its die holder by suitable bolts, and includes a cutting wire base 244 positioned thereon by means of locating pins 246 and spring loaded lock pins 248. The base 244 carries an adjustable wire anchor 250 at its one end and an adjustable wire tension screw 252 at its other end. A wire 254 extends between the anchor 250 and the tension screw 252. The wire 254 is designated as a cold wire, since it is not The wire 254 may be formed of piano-wire steel or of nylon, and is tightly tensioned to provide a substantially rigid cutting edge.

The hot die body 240' is movably secured within its die holder by means of a central pivot pin 256, and carries end pieces 258 and 260 at its opposite ends. The end pieces 258 and 260 are pivo-tally secured by means of pins 262 and are outwardly biased by suitable springs 264. An impulse type heater element 266 of flat strip form extends between the end pieces 258 and 260. A

hot die lining member 268 is secured to the face of the bot die body 240, and portions thereof at opposite sides of the heater element 266 serve to support channel clips 270 and 271 for mounting elongated gripper members 272 and 273 of neoprene rubber or the like (see FIGURE 12). Corresponding channel clips 274 and 275 are carried by the face of the cutting die body 242, and serve to support corresponding pairs of rubber grippers 276 and 277. A cold wire back-up member 278, also of neoprene rubber or the like, is carried by a suitable clip 280 on the cutting die body 242 intermediate the grippers 276, 277 and in directly opposed relation to the heater element 266 of the hot die body 240. The back-up member 278 underlies and contactingly supports the tensioned cold wire 254 to provide a stable but resilient backing surface.

As best seen in FIGURE 12 of the drawing, sealing engagement of the die bodies 240 and 242 will effect a gripping engagement of the hollow tube of polyethylene packaging material between the opposed pairs of neoprene rubber grippers 272, 273 and 276, 277. At the same time, the tension-relieved webs of polyethylene extending across the tightly engaged rubber grippers will be contacted by the heating element 266, the back-up member 278, and the cold wire 254 therebetween. The cooperative engagement of these parts will serve to effect a heat sealing of the polyethylene material to provide an upper end closure for the lower package and a lower end closure for the upper package. The cold wire 254 will serve to sever the heat sealed portion substantially at its mid-line.

Because of the complete interchangeability of the various sealing die assemblies Within the die holders, it is possible to quickly select and provide the desired sealing die means appropriate to the particular packaging material to be employed in the machine. The structure of FIGURES 8 and 9 may be readily employed with cellophane and substantially all heat sensitive coated papers. The structure of FIGURES 10 to 12 is particularly adapted for efiicient operation with polyethylene.

In order to provide the hollow and continuous tube of packaging material upon which the sealing die assemblies efiect their sealing and drawing operations, a suitable tube-forming mechanism is provided within the upper section A of the machine, immediately above the package-forming and drawing section B. Such a tube forming mechanism may be of the conventional and wellknown type comprising a hollow tubular mandrel 290 and a cooperating edge sealing platen 292 of the heatsealing type. Such structures are conventional and well known, and do not form a part of the present invention. It will be clear to those skilled in the art that a fiat web of packaging material will be carried from suitable supply rolls over a folding bar and around the mandrel 290 for edge sealing into tubular form by the heat sealing means 292. The drawing action of the sealing assemblies heretofore described will serve to pull the packaging material web through the tube forming structure 290' and 292, in the well known manner.

It is common practice in the packaging art to employ packaging materials which are imprinted or otherwise decorated. In order to utilize a continuous web of packaging material having successive impressions thereon of the printing and decoration which is desired for each separate final package of the pillow-type, it is critically important in such machines to provide means for insuring registration of the packaging material in direct correspondence with a pre-selected length of package. Although various mechanisms and devices have been suggested in the past for accomplishing this need for web registration, it is an important feature of the present invention to provide a simple but efiicient means for accomplishing registration with reliability during high-speed machine operation.

For this purpose we have provided a novel lock release principle of operation for the web feed to accomplish package registration. First, the over-all length of the printed package material for a designated final package length is determined, and the stroke adjustment slide 68 of the drive section C of the machine is appropriately positioned so that the operation of the walking beam 48 will effect a package drawing through a length of stroke which is slightly greater than the final desired package length. In practice, a stroke length of about to A inch greater than the desired package length is selected. A photo-electric cell, or electronic reset scanner of conventional and well known type, not shown but indicated diagrammatically in FIGURE 16 at P, is suitably mounted at the upper end of the machine within the tube-forming section A for detecting the passage of the web material. The web material is provided with a suitable marking point which can be detected by the scanner for automatically determining a package length of the printed material, again in the well known manner. The scanning device is electrically coupled by means of a suitable reversing relay R to solenoid valves V and V disposed in the pressure lines 184 and 186, respectively, which supply the hydraulic cylinders 154 of each of the sealing jaw carriages and 82. When the scanner is actuated by the web marking which indicates a desig nated package length, the solenoid valves are alternately actuated to effect pressure release of the hydraulic lock mechanism and clamp block 152 of a corresponding jaw carriage. Although the sealing jaw carriages continue their downward movement after such hydraulic pressure release, tight gripping engagement of the packaging material is no longer maintained, and the sealed package end effects a slippage through the sealing jaws. In this way, the package is released about /8 to 4 inch before completion of the drawing stroke.

This lock release principle of package registration eliminates all stretching of the packaging material, such as characterizes previously known registration devices. When materials such as polyethylene or Saran are employed, the use of pull-back systems of registration, of the type which have been commonly employed in the past are not acceptable because of the undesirable stretching which occurs in the packaging material. Such stretching risks package tearing and results in a malformed appearance in the final package.

The supply rolls of the packaging material to be used are particularly adapted for operation with this novel lock release principle by providing a substantially continuous brake drag on the withdrawal of the material from the supply rolls. As will now appear from the following description of the supply roll mounting and cooperating brake means, successive package drawings and tension releases in accordance with the lock release principle de scribed above will result in a hunting action by the applied brake forces against the supply roll so as to provide a cyclical increase and decrease in the braking or drag applied thereon which correspondingly follows the cyclical increase and decrease of tension of the withdrawn web during machine operation.

Referring now more particularly to FIGURES 13 and 14 of the drawing, we have illustrated a mounting of two web supply rolls 294 and 296 in vertically superposed relation at the lower rear portion of the machine. As is well understood in connection with pillow-type packaging machines, Webs W of packaging material may be simultaneously withdrawn from both rolls and carried in overlying relation through the tube-forming mechanism so as to form a packaging tube of double wall thickness. Such supply rolls may also be used singly and successively as desired for packages of single web thickness.

The mounting and brake structure of each of the rolls 294 and 296 is substantially identical, and the following description of the structure of one of the rolls is typical. A roll support shaft 298 serves to mount the roll 294. A brake support plate 300 provides a mounting structure for the brake means. A brake shoe 302 overlies the shaft 298 and is adapted to efiect braking engagement against a brake drum 303 carried by the shaft 298. A brake shoe actuator arm 304 extends pivotally from the shoe 302 and rides upon an eccentric brake actuator cam 306. A support arm 308 rotatably carries the brake actuator 306, and serves to mount an idler roller shaft 310 at its free end. The web W is withdrawn from the outermost convolution of the roll of web material and passes below and upwardly around the idler roller 310. The web then extends up the height of the machine and over a suitable folder bar to the tube forming mandrel 290.

It will be apparent that as the webs W of each of the rollers 294 and 296 are drawn upwardly by package formthe reciprocating sealing jaw carriages.

.temperature for the die heaters. 214 will be substantially the same in temperature as the control heater 214.

ing strokes of the carriage assemblies 80 and 82, the idler rollers 310 will be carried slightly upwardly as the support arms 208 effect a pivoting movement and consequent lowering of the eccentric brake actuator cams 306. The brake shoes 302 will be relieved of any braking force tending to eficct their engagement against the roll shaft drums 303. When the webs are released at the end of a package forming stroke, however, gravity will cause the support arms 308 and the idler rollers 31% to effect a downward pivotal movement tending to elevate the actuator cams 306 upwardly against the brake shoe actuator arms 304. Such movement will cause the brake shoes '302 to effect engagement against the roller shaft drums 303, thereby exerting a braking drag against further web withdrawal. Such action will be repeated cyclically during continuous machine operation and will serve to effect .a brake hunting tending to maintain a controlled force against the supply rolls.

FIGURE 15 of the drawing provides a complete timing chart of the machine operation which has been completely described and set forth above. This chart is provided as a quick visual representation of the various coordinating movements of the related machine components ,and controls. Solid lines have been used to designate the operation of the right-side carriage assembly 82 and dotted lines to represent the left-side carriage assembly 80.

FIGURE 16 has also been provided as a quick visual representation of the hydraulic flow system for actuating the die clamping cylinders, as has been described in de- .tail above in connection with FIGURE of the drawing. FIGURE 17 is a further diagrammatic representation for quick visual identification of the flow path from FIGURE 18 has been provided to illustrate a remote thermostatic control circuit for the die'heater 214 of .the cellophane-type sealing die assembly described above .in connection with FIGURES 8 and 9. Because of space limitations and the desirability of making control adjustvments during machine operation, we have provided a re- -mote thermostatic control means for the die heater.

A control of phantom heater 214', identical in every re- .spect with the main die heaters 214, is disposed at some convenient fixed location in the machine remote from A thermostatic switch T may be preset to maintain a desired operating The actual die heaters In this way adjustments in thermostatic control can be made while the machine is running;

a single adjustable thermostatically controlled heater 214' may be used for Controlling the die heaters of both carriage assemblies; a relay may be employed with separate .Wires to each die if desired; impact shock on the thermostat is eliminated because of its fixed location remote from the moving carriages; and less expensive die struc- -tures may be employed with minimum space requirements.

Summary of Practical Operation Referring now more particularly to FIGURES l and 2 of the drawing, the over-all operation of the machine will be summarized for the purpose of providing particular emphasis to the various novel features which distinguish the present invention over previously known drawtype wrapping machines. In accordance with the well known basic principle of draw type wrapping, a fiat web of packaging material is withdrawn from a supply roll land bent against itself about a tube-forming mandrel 290 dies 90 and 2 of a first carriage assembly 80 are posttioned in spaced or-open, relation at opposite sides of the packaging tube adjacent the upper end of the machine, and immediately below the heat sealing mechanism 292 and the lower terminal end of the hollow mandrel 290. As the dies 99 and 92 are brought into closed relation, an end seal is applied to the tube of packaging material and tight gripping engagement thereof is maintained. The material to be packaged is delivered through the hollow mandrel 290 into the now closed-end packaging tube. The closed dies are then carried downwardly by their reciprocating carriage so as to draw the tube downwardly therewith. At the same time, the jaws and 92 of the other carriage assembly 82 are maintained in open relation as they are carried upwardly around each side of the closed drawing dies of carriage assembly 80. When the closed dies of the carriage assembly 86 have reached the lowermost position of the drawing stroke, the open dies of the carriage assembly 32 will have moved upwardly therearound to the uppermost position of carriage stroke. The lower closed dies will then open as the upper open dies eifect their closure in turn, and the reciprocating drawing cycle will be continuously repeated in the manner of a hand-over-hand pulling operation.

In order to provide simple and efficient stroke adjustment for this type of drawing machine structure, we have provided the novel walking beam 48 for oscillating-drive reciprocation of the carriage assemblies. This particular form of mechanical drive, and the adjustable variation of the position of the fulcrum point of the walking beam 48, serves to enable variation in the amplitude of oscillation of the walking beam, thereby permitting selective predetermination of the height of the strokes of the carriage supporting rods. This feature of rod stroke adjustment enables the desired packaged length to be readily selected.

In order to insure tight closing action of the dies, and the maintenance of a predetermined sealing pressure throughout the downward drawing stroke, we have provided a novel two-stage closure mechanism for the sealing dies. First, a mechanical pivoting action is effected to swing the dies into kissing contact. Second, a hydraulic squeeze is applied to effect tight gripping of the packaging material between the die faces. This hydraulic pressure is maintained at a constant pressure level and effects a fixed locking of the dies throughout the downward drawing stroke.

The particular sealing die-assemblies are mounted for selective interchangeability so as to readily adapt the machine for use with various packaging materials. In order to effect separation of a completed package at the end of the drawing stroke, a cutting action is performed by one formof sealing dies. Contrary to prior practice, wherein the dies effect blade cutting as they perform the initial sealing closure at the top of the stroke, we have provided a novel recessed cutting blade which is automatically actuated midway along the length of the downward drawing stroke. In this way, the cutting operation is not performed until substantial heat sealing has been etfected bedded within the hot dies may be provided at a location remote from the reciprocating carriage structures. This control is achieved by means of a phantom control heater which duplicates the action of the actual jaw heater, so that its temperature may be readily sensed, adjusted and controlled.

In order to provide full adaptability of the machine for use with polyethylene as a packaging material, we have provided an alternative sealing die structure which may be readily mounted on the jaw carriages in place of the knife-cutting type of sealing dies. This die assembly provides opposed pairs of rubber grippers for effecting engagement of the polyethylene tube and for relieving tension of a portion of the web therebetween for sealing 13 action. An impulse heating element eflects engagement with the tensioned web and simultaneously applies pressure upon the web against a cold wire cutter and a resilient backing surface. In this way, impulse heat sealing of the package is effected simultaneously with a cutting action across the sealed surfaces.

In order to provide simple but efficient means for insuring package length registration, we have provided a novel lock release principle of operation for the packaging web feed. Supply rolls having frictional brake means adapted to effect a substantially uniform drag against web Withdrawal are provided so that as the machine drawing process is cyclically repeated the brake means will perform a hunting operation tending to maintain a controlled drag force against the supply rolls. This braking means is of particular importance in connection with the lock release principle of web registration.

The lock release operation is performed by selecting a predetermined length of printed package material for a designated final length of the pillow-type package. The stroke adjustment mechanism of the walking beam is then appropriately positioned so that the length of carriage strokes will be slightly greater than the final desired package length. Suitable photo-electric means serves to detect the designated length of printed packaging material and to actuate suitable solenoid valve means for venting the hydraulic pressure of the sealing die locking mechanism. Although the jaw carriages will continue full movement through their drawing stroke after hydraulic pressure release, the locked gripping engagement of the packaging material will no longer be maintained, and slippage of the sealed package end will occur between the sealing jaws, thereby releasing the complete and severed package before completion of the drawing stroke but at the desired package length.

These improved structural features and operating techniques serve to provide a draw-type wrapping machine of greatly improved performance, flexibility, and reliability over previously known draw-type wrapping machines.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A dual'action draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and edge sealing means operative to form said web into a continuous hollow tube, a pair of sealing jaw carriages mounted in opposed overlapping relation, a pair of sealing dies carried by each carriage and movable to closed engagement with said tube, means to alternately reciprocate said jaw carriages in opposite directions, said reciprocating means including a walking beam member having one end secured to one carriage and the other end secured to the other carriage and being pivotally mounted intermediate said ends, and actuator means pivotally secured to said walking beam intermediate its pivotal mounting and one of its ends to eifect oscillation of said walking beam and thereby alternately reciprocate said carriages, said actuator means being selectively adjustable to vary the amplitude of oscillation of said walking beam and thereby vary the length of the reciprocating stroke of said carriages.

2. A dual-action draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and edge sealing means operative to form said web into a continuous hollow tube, a pair of sealing jaw carriages mounted in opposed overlapping relation, a pair of sealing dies carried by each carriage and movable to closed engagement with said tube, means to alternately reciprocate said jaw carriages in opposite directions, said 14 reciprocating means including a walking beam member having one end secured to one carriage and the other end secured to the other carriage and being pivotally mounted intermediate said ends, actuator means pivotally secured to said walking beam intermediate its pivotal mounting and one of its ends, and means for reciprocating said actuator means to efiect oscillation of said walking beam and thereby alternately reciprocate said carriages, the length of stroke of said reciprocating actuator means being selectively adjustable to vary the amplitude of oscillation of said walking beam and thereby vary the length of the reciprocating stroke of said carriages.

3. A draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and 15 edge sealing means operative to form said web into a continuous hollow tube, a sealing jaw carriage having a passageway therein, a pair of sealing dies carried by said carriage and movable to closed engagement with said tube, means for reciprocating said sealing jaw carriage through a tube-drawing stroke, mechanical drive means including linkage associated with said carriage for alternately closing and opening said dies, and means including said sealing jaw carriage passageway for thereafter applying hydraulic pressure to the closed dies independently of said 2 linkage for effecting squeezing closure of said dies, said locking means being operative to maintain said dies in locked relation throughout the tube-drawing stroke of said carriage.

4. A draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and edge sealing means operative to form said web into a continuous hollow tube, a sealing jaw carriage having a passageway therein, a pair of sealing dies carried by said carriage and movable to closed engagement with said tube, means for reciprocating said sealing jaw carriage through a tube-drawing stroke, mechanical drive means including linkage associated with said carriage for alternately closing and opening said dies, and means including said sealing jaw carriage passageway for thereafter applying hydraulic pressure to the closed dies independently of said linkage for effecting final squeezing closure of said dies, said locking means being operative to maintain said dies in locked relation throughout the tube-drawing stroke of said carriage, and detector means for measuring a predetermined package length of said web, said detector means being operative to release said locking means in response to a length of said tube-drawing stroke equal to said web package length.

5. A draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and edge sealing means operative to form said web into a continuous hollow tube, a sealing jaw carriage having a passageway therein, a pair of sealing dies carried by said carriage and movable to closed engagement with said tube, means for reciprocating said sealing jaw carriage through a tube-drawing stroke, mechanical drive means including linkage associated with said carriage for alternately closing and opening said dies, and means including said sealing jaw carriage passageway for thereafter applying hydraulic pressure to the closed dies independently of said linkage for efiecting final squeezing closure of said dies and including pressure-fluid supply means, valve means for relieving said fluid-pressure supply means, said locking means being operative when pressurized to maintain said dies in locked relation throughout the tube-drawing stroke of said carriage, and detector means for measuring a predetermined package length of said web, said detector means being operative to actuate said valve means and thereby efiect pressure release of said locking means in response to a length of said tube-drawing stroke equal to said web package length.

6. A dual-action draw-type wrapping machine comprising a supply of packaging material in web form, a tube former and edge sealing means operative to form said web into a continuous hollow tube, a pair of sealing jaw carriages mounted in opposed overlapping relation, a pair of sealing dies carried by each carriage and movable to closed engagement with said tube, means to alternately reciprocate said jaw carriages in opposite directions, mechanical drive means for alternately closing and opening said dies of each carriage, hydraulic locking means for eifecting squeezing closure of said dies of each carriage and including separate pressure-fluid supply means, separate solenoid-controlled valve means for relieving each of said fluid-pressure supply means, each of said locking means being operative when pressurized to maintain its corresponding dies in locked relation throughout the tubedrawing stroke of the carriage, photoelectric detector means for measuring a predetermined package length of said web, and reversing relay means electrically interconnecting said detector means with both of said valve means, said detector means being operative to alternately actuate each of said valve means and thereby efiect release of a corresponding one of said locking means at the lower end of its drawing stroke in response to a length of said tube-drawing stroke equal to said web package length.

7. An arrangement for closing a pair of die members about a moving tubular thermoplastic element in a cyclical operation wherein a carriage supporting said die holders is reciprocated longitudinally with respect to said thermoplastic element, the improvement comprising mechanically operated means associated with said carriage for closing said die holders about said thermoplastic element at a predetermined position with respect thereto, a hydraulic cylinder carried by said carriage, a rigid wall conduit formed in said carriage for communicating fluid under pressure with said hydraulic cylinder, means operated responsive to fluid pressure applied to said cylinder for clos ing said die holders more tightly about said element, and means operated after the closure of said die holders by said mechanically operated means for thereafter applying fluid pressure to said conduit and said hydraulic cylinder to operate said means for closing said die holders more tightly about said element.

References Cited in the file of this patent UNITED STATES PATENTS 2,199,708 Maxfield May '7, 1940 2,265,253 Smith Dec. 9, 1941 2,869,298 Zwoyer Jan. 20, 1959 

